There's only one of me, and yes, I bought a TomTom 510 for my wife a few weeks back. It's superb, she says 'better than I expected'.
Anything that can get her from home to an obscure address in a village 100 miles from home and back without a single hitch has got to be good, and that's exactly what happened a week after I bought it.
I used my link and in a few days I hope (expect) to get a 510 at the price I quoted above, the link works but you can only get home delivery not reserve and collect. Delivery is free but takes up to 7 days, undefined time.
The wide screen gives good visibility of the maps, and makes this a good choice for the motorist. Also, the unit is very reliable - no need for the resets that other brands seem to need. The Bluetooth connectivity is very useful too for hands-free phone calls.
It has fewer routing options than other brands - you can select fastest or shortest route, or off-road (for walkers), but no options for motorways verus A-roads etc.
If you are a good linguist you'll have no problem with the 610. However, a problem with the unit is that the British English voice prompts can just disappear completely - for good. You'll still have 19 other language options, but you will need to learn the German/French/Italian etc for 'at the roundabout, take the 3rd exit'.